Intraoral scanner with fixed focal position and/or motion tracking

Abstract

An apparatus for measuring a surface topography of a patient's teeth may include an optical probe, a light source configured to generate incident light, and focusing optics configured to focus one or more wavelengths of the incident light to a fixed focal position external to the optical probe, wherein the fixed focal position is fixed relative to the optical probe. The apparatus may further include a light sensor configured to measure a characteristic of returned light generated by illuminating the patient's teeth with the incident light and a processing unit operable to determine the surface topography of the patient's teeth based on the measured characteristic of the returned light.

What is claimed is: 
     
       1. An apparatus for measuring a surface topography of a patient's teeth, the apparatus comprising:
 an optical probe; 
 a light source configured to generate incident light; 
 focusing optics configured to focus one or more wavelengths of the incident light to a fixed focal position external to the optical probe, wherein the fixed focal position is fixed relative to the optical probe; 
 a light sensor configured to measure a characteristic of returned light generated by illuminating the patient's teeth with the incident light; and 
 a processing unit operable to determine the surface topography of the patient's teeth based on the measured characteristic of the returned light. 
 
     
     
       2. The apparatus of  claim 1 , further comprising:
 a motion tracking device configured to collect motion data during measurement of the characteristic of said returned light; 
 wherein the processing unit is operable to determine the surface topography of the patient's teeth based on the measured characteristic of said returned light and the motion data. 
 
     
     
       3. The apparatus of  claim 1 , wherein:
 the incident light comprises a plurality of incident light rays; and 
 the focusing optics are configured to focus each of the plurality of incident light rays to a respective fixed focal position relative to the optical probe. 
 
     
     
       4. The apparatus of  claim 3 , wherein some light rays of the plurality of incident light rays are focused to different focal lengths than other light rays of the plurality of incident light rays. 
     
     
       5. The apparatus of  claim 3 , wherein the respective fixed focal positions of the plurality of incident light rays form a diagonal focal plane that is non-orthogonal to a direction of propagation of the plurality of incident light rays. 
     
     
       6. The apparatus of  claim 1 , wherein the incident light comprises an array of incident light beams, the apparatus further comprising:
 a micro lens array for focusing the array of incident light beams onto respective fixed focal positions, wherein micro lenses of the micro lens array are arranged in a plurality of rows. 
 
     
     
       7. The apparatus of  claim 1 , wherein the incident light comprises an array of incident light beams, the apparatus further comprising:
 a source array for focusing the array of incident light beams onto respective fixed focal positions, wherein the source array is tilted respective to an optical axis of the focusing optics. 
 
     
     
       8. The apparatus of  claim 1 , wherein the characteristic of the returned light comprises intensity. 
     
     
       9. The apparatus of  claim 1 , wherein a direction of propagation of the incident light is orthogonal to an optical axis of the focusing optics. 
     
     
       10. The apparatus of  claim 1 , wherein a direction of propagation of the incident light is non-orthogonal to an optical axis of the focusing optics. 
     
     
       11. The apparatus of  claim 1 , wherein the incident light comprises a plurality of incident light beams and the returned light comprises a plurality of returned light beams, the apparatus further comprising:
 a two-dimensional array of sensor elements, each sensor element of the two-dimensional array of sensor elements being configured to measure the characteristic of the returned light from a corresponding returned light beam of the plurality of returned light beams. 
 
     
     
       12. The apparatus of  claim 11 , wherein the focusing optics is configured to form a two-dimensional pattern of the plurality of incident light beams from the incident light generated by the light source, the two-dimensional pattern of the plurality of incident light beams corresponding to the plurality of returned light beams measured by the two-dimensional array of sensor elements. 
     
     
       13. The apparatus of  claim 11 , wherein the fixed focal position is between 5 mm and 25 mm from the optical probe. 
     
     
       14. The apparatus of  claim 1 , wherein the focusing optics comprise confocal focusing optics. 
     
     
       15. An apparatus for measuring a surface topography of a patient's teeth, the apparatus comprising:
 an optical probe; 
 a light source configured to generate incident light; 
 focusing optics configured to focus the incident light to one or more focal position external to the optical probe; 
 a light sensor configured to measure a characteristic of returned light generated by illuminating the patient's teeth with the incident light; 
 a motion tracking device configured to collect motion data during measurement of the characteristic of the returned light; and 
 a processing unit operable to determine the surface topography of the patient's teeth based on the measured characteristic of the returned light and the motion data. 
 
     
     
       16. The apparatus of  claim 15 , wherein the incident light comprises a plurality of incident light beams and the returned light comprises a plurality of returned light beams, the apparatus further comprising:
 a two-dimensional array of sensor elements, each sensor element of the two-dimensional array of sensor elements being configured to measure the characteristic of the returned light from a corresponding returned light beam of the plurality of returned light beams. 
 
     
     
       17. The apparatus of  claim 16 , wherein the focusing optics is configured to form a two-dimensional pattern of the plurality of incident light beams, the two-dimensional pattern of the plurality of incident light beams corresponding to the plurality of returned light beams measured by the two-dimensional array of sensor elements. 
     
     
       18. The apparatus of  claim 15 , wherein the motion data comprises inertial measurement data. 
     
     
       19. The apparatus of  claim 15 , wherein the characteristic of the returned light comprises intensity. 
     
     
       20. A method for measuring surface topography of a patient's teeth using an optical probe, the method comprising:
 generating incident light by a light source; 
 focusing, using focusing optics, at least a first wavelength component of the incident light to a fixed focal position relative to an optical probe while measuring the surface topology of the patient's teeth; and 
 measuring a characteristic of returned light that is generated by illuminating the patient's teeth with the incident light for one or more of a plurality of different relative positions or a plurality of different relative orientations between the optical probe and the patient's teeth in order to measure the surface topology of the patient's teeth. 
 
     
     
       21. The method of  claim 20 , wherein the characteristic of the returned light comprises intensity. 
     
     
       22. The method of  claim 20 , wherein the incident light comprises a plurality of incident light rays, the method further comprising:
 focusing each of the plurality of incident light rays to a respective fixed focal position relative to the optical probe.